Ocular and systemic risk factors associated with glaucomatous visual field defect in normal tension glaucoma

Objectives: The purpose of the study is to assess the systemic and ocular risk factors for normal tension glaucoma (NTG) and look into how they relate to the degree of glaucomatous damage in the visual field, with an emphasis on the affected patients’ intraocular pressure (IOP), cup-to-disc (CD) ratio, central corneal thickness (CCT), systemic comorbidities, and optic disc changes. Material and Methods: This cross-sectional study was done on 67 patients. Demographic data, ocular parameters, systemic comorbidities, and visual field changes were analyzed. Key variables included IOP, CD ratio, CCT, and optic disc findings. Correlation and association analyses were performed to identify significant relationships between risk factors and glaucomatous visual field changes. Results: The mean age of participants was 59.3 ± 10.4 years. Males constituted 58.2% of the cohort, and 25.4% had a family history of glaucoma. IOP ranged from 8 to 21 mmHg (mean: 15.3 ± 3.2 mmHg). The mean CD ratio was 0.69 ± 0.13. The average CCT was 525.8 ± 44.7 µm. Systemic comorbidities included hypertension (71.6%), diabetes mellitus (49.3%), dyslipidemia (43.3%), smoking (28.4%), ischemic heart disease (19.4%), and Alzheimer’s disease (3%). Visual field changes were predominantly early stage (35.8%) or pre-perimetric (31.3%), while 22.4% had advanced-stage changes. Optic disc findings included neuroretinal rim thinning (47.8%), disc hemorrhage (14.9%), and pale discs (3%). No significant differences were found between age, gender, diabetes, hypertension, or dyslipidemia across different stages of glaucomatous visual field changes, except for thyroid disorders ( P = 0.038). CD ratio increased with the advancement of the staging of glaucomatous visual field defect ( P = 0.045). There was a weak positive correlation of age (ρ = 0.248, P = 0.043) and a moderate positive correlation of CD ratio (ρ = 0.364, P = 0.002) with glaucomatous field defect. Conclusion: This study highlights that among NTG patients, thyroid disorders and CD ratio demonstrated significant associations with glaucomatous changes.